Table 45: Junos Os Processes - Juniper JUNOS OS 10.3 - SOFTWARE Manual

Routing Engine and Packet Forwarding Engine
Junos OS Processes

Table 45: Junos OS Processes

Process Name
Chassis process chassisd
Ethernet eswd
switching
process
Forwarding pfem
process
Interface dcd
process
Copyright © 2010, Juniper Networks, Inc.
A switch has two primary software processing components:
Packet Forwarding Engine—Processes packets; applies filters, routing policies, and
other features; and forwards packets to the next hop along the route to their final
destination.
Routing Engine—Provides three main functions:
Creates the packet forwarding switch fabric for the switch, providing route lookup,
filtering, and switching on incoming data packets, then directing outbound packets
to the appropriate interface for transmission to the network
Maintains the routing tables used by the switch and controls the routing protocols
that run on the switch.
Provides control and monitoring functions for the switch, including controlling power
and monitoring system status.
The Junos OS running on the Routing Engine and Packet Forwarding Engine consists of
multiple processes that are responsible for individual functions.
The separation of functions provides operational stability, because each process accesses
its own protected memory space. In addition, because each process is a separate software
package, you can selectively upgrade all or part of the Junos OS, for added flexibility.
Table 17 on page 24 describes the primary Junos OS processes.
Description
Detects hardware on the system that is used to configure network interfaces.
Monitors the physical status of hardware components and field-replaceable units
(FRUs), detecting when environment sensors such as temperature sensors are triggered.
Relays signals and interrupts—for example, when devices are taken offline, so that the
system can close sessions and shut down gracefully.
Handles Layer 2 switching functionality such as MAC address learning, Spanning Tree
protocol and access port security. The process is also responsible for managing Ethernet
switching interfaces, VLANs, and VLAN interfaces.
Manages Ethernet switching interfaces, VLANs, and VLAN interfaces.
Defines how routing protocols operate on the switch. The overall performance of the
switch is largely determined by the effectiveness of the forwarding process.
Configures and monitors network interfaces by defining physical characteristics such
as link encapsulation, hold times, and keepalive timers.
Chapter 14: System Setup Overview
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